Re:How Do Computers Generate Random Numbers?
by DanBC on Monday September 14, 2020 @05:16AM
(#24468238)
The Von Neumann extractor is interesting.
> Von Neumann’s originally proposes the following technique for getting an unbiased result from a biased coin :
> > If independence of successive tosses is assumed, we can reconstruct a 50-50 chance out of even a badly biased coin by tossing twice. If we get heads-heads or tails-tails, we reject the tosses and try again. If we get heads-tails (or tails-heads), we accept the result as heads (or tails).
Re:How Do Computers Generate Random Numbers?
by ImaCake on Monday September 14, 2020 @08:17AM
(#24469195)
That is a fantastic resource. It never occured to me that such a thing would exist, but now that I know it does, I find it hard to think of how it wouldn't - since so much of the internet would rely on these kind of tricks to keep working.
Only practical use for me would be to confound markers trying to reproduce my RNG's in statistics assignments.
The idea is to count the number of events (beta particles here) per time interval. Do this twice. If count A > count B, output a 1. If count A < count B, output a 0. If count A = count B, skip that result. Von Neumann came up with that trick.
Don't use the low-order bit of the count. That has a bias.
[1] https://www.fourmilab.ch/hotbits/